Hydroxyl terminated liquid polymers are useful as polyols in the formation of polyurethanes. In such reactions a hydroxyl terminated liquid polymer is reacted with an organic diisocyanate to form high molecular weight polyurethanes. In many instances it has been found that the hydroxyl terminated liquid polymers have been excessively active in reactions with the organic diisocyanate, resulting in premature gellation and excessive exotherms because of the rapid reactions which are often uncontrolled and may result in insoluble masses in short periods of time.